Linus' sha1 is much faster!

I've noticed before that coreutils hashing utils
were a little behind in performance, but was prompted
to look at it again when I noticed the recently
updated sha1 implementation in git:
http://git.kernel.org/?p=git/git.git;a=history;f=block-sha1;h=d3121f7;hb=pu

Testing that with the attached program which I wrote
in a couple of mins to try and match sha1sum's system calls
shows that it's around 33% faster, as shown below:

$ gcc $(rpm -q --qf="%{OPTFLAGS}\n" coreutils) linus-sha1.c sha1.c -o linus-sha1

$ time ./linus-sha1 300MB_file
df1e19e245fee4f53087b50ef953ca2c8d1644d7  300MB_file
real    0m2.742s
user    0m2.516s
sys     0m0.206s

$ time ~/git/coreutils/src/sha1sum 300MB_file
df1e19e245fee4f53087b50ef953ca2c8d1644d7  300MB_file

real    0m4.166s
user    0m3.846s
sys     0m0.298s

So, could we use that code in coreutils?
Think of all the dead fish it would save.

I've also attached a trivial block-sha1 patch which doesn't
affect performance, but does suppress a signed unsigned
comparison warning which occurs with -Wextra for example.

cheers,
Pádraig.